<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[hy3131的博客]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/hy3131</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; hy3131]]></copyright><item><title><![CDATA[HBase-思维导图]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124651454</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124651454</guid><author>hy3131</author><pubDate>Sun, 08 May 2022 17:38:49 +0800</pubDate><description><![CDATA[]]></description><category></category></item><item><title><![CDATA[网络爬虫-四种统计图]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124651335</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124651335</guid><author>hy3131</author><pubDate>Sun, 08 May 2022 17:35:46 +0800</pubDate><description><![CDATA[1，柱状图
import numpy as np
import matplotlib.pyplot as plt

#准备数据
x=np.array(['baseketball','football','baseball','beautiful',])
y=np.array([10,20,20,9])
c=np.array(['#4CAF50','red','hotpink','#556B2F'])
#插入数据
plt.bar(x,y,color=c,width=0.5)
plt.title('hobby']]></description><category></category></item><item><title><![CDATA[Hadoop-代码统计文本单词]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124651293</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124651293</guid><author>hy3131</author><pubDate>Sun, 08 May 2022 17:29:07 +0800</pubDate><description><![CDATA[import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib]]></description><category></category></item><item><title><![CDATA[hadoop_WordCountMap]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124526597</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124526597</guid><author>hy3131</author><pubDate>Sun, 01 May 2022 14:21:31 +0800</pubDate><description><![CDATA[import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Mapper;

import java.io.IOException;

/*LongWritable 偏移量 Long，表示该行在文件中的位置，而不是行号

* Text map阶段的输入数据 一行]]></description><category></category></item><item><title><![CDATA[mysql查询优化和参数优化]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124526559</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124526559</guid><author>hy3131</author><pubDate>Sun, 01 May 2022 14:19:09 +0800</pubDate><description><![CDATA[#避免全表扫描
use test;
create table if not exists t(id int,num int defalult 0,name varchar(20));
create index ix_num on t(num);
#避免查询null 
#未使用索引
select id from t where num=null;
#使用索引
select id from t where num=0;
#避免使用!=、&lt;&gt;(也是!=) 未使用索引
select * from t .]]></description><category></category></item><item><title><![CDATA[爬虫_pandas]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124526507</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124526507</guid><author>hy3131</author><pubDate>Sun, 01 May 2022 14:17:12 +0800</pubDate><description><![CDATA[123.py
import pandas as pd

df=pd.read_csv('./123.csv')

打印某一列;判断某一列是否有空值
print(df['NUM_BEDROOMS'])
print(df['NUM_BEDROOMS'].isnull())
dropna()中写inplace=True修改源数据
df2=df.dropna()
指定的列的某一行有空值的话就删除那一行数据


df3=df.dropna(subset=['ST_NUM']) 
替换脏数据为666 
df4=df..]]></description><category></category></item><item><title><![CDATA[网络爬虫__numpy]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124271429</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124271429</guid><author>hy3131</author><pubDate>Tue, 19 Apr 2022 13:38:32 +0800</pubDate><description><![CDATA[下载numpy包

from numpy import *

print(eye(4)) 打印4行4列的数组，每个数后面都有小数点，第n行第n列的数都为一，其余为0（1&lt;=n&lt;=4）import numpy as np

import numpy as np

a=np.array([1,2,3])创建一个ndarray对象 ndarray是多维数组 dimensional 维度

print(a.dtype)打印数据类型 int32表示4字节的整形

print(a.shape)打印数组的元素]]></description><category></category></item><item><title><![CDATA[SQL扫描]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124266745</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124266745</guid><author>hy3131</author><pubDate>Tue, 19 Apr 2022 10:11:17 +0800</pubDate><description><![CDATA[select(select count(*) from city)-count(*) from city where id&lt;=5;这样的语句不用全表扫描，提高了效率，这条语句扫描了6次 小括号中的查询语句没有进行全表扫描，sql知道有多少行数，

count(*) from city where id&lt;=5 sql语句中的这一部分语句查询了5行数据 

select * from city where id&gt;5;扫描了95次

select count(*) from city;速度...]]></description><category></category></item><item><title><![CDATA[Linux__hadoop免密登录&JavaToJDFS]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124266604</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124266604</guid><author>hy3131</author><pubDate>Tue, 19 Apr 2022 10:05:00 +0800</pubDate><description><![CDATA[配置ssh免登陆

生成ssh免登陆密钥

cd ~，进入到我的home目录

cd .ssh/

ssh-keygen -t rsa （四个回车）

执行完这个命令后，会生成两个文件id_rsa（私钥）、id_rsa.pub（公钥）

将公钥拷贝到要免登陆的机器上

cat ~/.ssh/id_rsa.pub &gt;&gt; ~/.ssh/authorized_keys cat是查看

或

ssh-copy-id -i localhost

关闭所有

stop-all.sh

开启所有

start]]></description><category></category></item><item><title><![CDATA[数据库_存储过程&范式]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124075491</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124075491</guid><author>hy3131</author><pubDate>Sun, 10 Apr 2022 11:44:49 +0800</pubDate><description><![CDATA[创建存 过程的外壳
delimiter $

create procedure test(userId int) begin

end $

delimiter ;

存储过程if(begin 和 end $之间)

1、声明变量username declare username varchar(32) default ' ';

2、if语句

if(userId%2=0)

then 　　#查询语句,将用户表的名字放到username变量 　　

select name into username fr]]></description><category></category></item><item><title><![CDATA[Hadoop大数据_安装jdk、hadoop]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124075409</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124075409</guid><author>hy3131</author><pubDate>Sun, 10 Apr 2022 11:40:49 +0800</pubDate><description><![CDATA[安装jdk

一、开启网络,ifconfig指令查看ip

二、修改主机名

hostnamectl set-hostname hadoop

三、查看防火墙状态并打开防火墙

1.firewall-cmd --state查看防火墙状态

2.systemctl start iptables.service打开防火墙

3.reboot 重启Linux

四、删除已有的jdk

查看java安装版本：java -version

查看java安装包：rpm -qa|grep java

删除java安装包：]]></description><category></category></item><item><title><![CDATA[网络爬虫_xpath]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/124075321</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/124075321</guid><author>hy3131</author><pubDate>Sun, 10 Apr 2022 11:37:35 +0800</pubDate><description><![CDATA[from lxml import etree
#https://mirrors.aliyun.com/pypi/simple/  python仓库
wb_data = """
  &lt;div&gt;
    &lt;ul&gt;
      &lt;li class="item-0"&gt;&lt;a href="link1.html"&gt;first item&lt;/a&gt;&lt;/li&gt;
      &lt;li class="item-1"&gt...]]></description><category></category></item><item><title><![CDATA[数据库_视图事物触发器存储过程]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/123940664</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/123940664</guid><author>hy3131</author><pubDate>Sun, 03 Apr 2022 17:19:20 +0800</pubDate><description><![CDATA[1.创建视图

create view 视图名(视图列1,视图列2)    视图列名为中文

as

select * from 表名                   没有指定那一列,从第一个列名开始创建

with check option;

2.添加视图数据、删除视图、查询视图、修改视图

和表一样的用法

3.创建多表视图

create view 视图名(视图列1,视图列2,视图列3)

as

select 列名1,列名2,列名3 from 表名1...]]></description><category></category></item><item><title><![CDATA[Linux_ssh服务、Linux自有服务、权限认识]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/123940566</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/123940566</guid><author>hy3131</author><pubDate>Sun, 03 Apr 2022 17:15:30 +0800</pubDate><description><![CDATA[ssh：安全外壳协议 端口号默认是22

如果要修改,则需要修改ssh服务的配置文件  修改范围：0-65535

服务启动/终止/重启

service sshd start/stop/restart

/etc/init.d/sshd start/stop/restart

获取服务器ip地址：ifconfig

pscp -r root@192.168.21.128:/etc E:\tmp   #将远程linux服务器下的/etc整个目录下载到电脑windows系统的E:\tmp下   ...]]></description><category></category></item><item><title><![CDATA[scrapy_爬虫]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/123940409</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/123940409</guid><author>hy3131</author><pubDate>Sun, 03 Apr 2022 17:09:34 +0800</pubDate><description><![CDATA[命令行下载jar包

pip install xxxxxx -i http://pypi.douban.com/simple --trusted-host pypi.douban.com
使用上面的命令下载wheel、lxml、twisted、pywin32、scrapy五个jar包，xxxxxx内填包名
命令行创建项目scrapy startproject yc  yc是项目名
创建py文件
scrapy genspider baidu www.baidu.com  baidu是文件名 文件名后...]]></description><category></category></item><item><title><![CDATA[Hadoop-shell脚本]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/123619837</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/123619837</guid><author>hy3131</author><pubDate>Sun, 20 Mar 2022 20:08:13 +0800</pubDate><description><![CDATA[1、什么是shell

什么是shell？

Shell（外壳）是一个用C语言编写的程序，它是用户使用Linux的桥梁。Shell既是一种命令语言，又是一种程序设计语言。Shell是指一种应用程序，这个应用程序提供了一个界面，用户通过这个界面访问操作系统内核的服务。

什么是脚本？

脚本简单地说就是一条条的文字命令，这些文字命令是可以看到的（如可以用记事本打开查看、编辑）。常见的脚本：JavaScript（JS，前端），VBScript，ASP，JSP，PHP（后端），SQL（数据库操作语言），Perl，]]></description><category></category></item><item><title><![CDATA[hbase索引]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/123619600</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/123619600</guid><author>hy3131</author><pubDate>Sun, 20 Mar 2022 19:50:30 +0800</pubDate><description><![CDATA[#创建数据库

CREATE DATABASE IF NOT EXISTS info DEFAULT CHARSET utf8;
USE info;
#创建表
CREATE TABLE IF NOT EXISTS emp(emp_id INT PRIMARY KEY AUTO_INCREMENT,
emp_name VARCHAR(20),
salary INT,
dept_id INT,
manager_id INT
);
SELECT * FROM emp WHERE emp_name = "父";

]]></description><category></category></item><item><title><![CDATA[Scrapy的使用和scrapy五大基本构成]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/123619125</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/123619125</guid><author>hy3131</author><pubDate>Sun, 20 Mar 2022 19:40:20 +0800</pubDate><description><![CDATA[目录

scrapy的使用

Scrapy五大基本构成:



from urllib import request

import re

#定义url

page=100

url='网站路径'

try:

  #定义请求头

  headers={'User-Agent':'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537...]]></description><category></category></item><item><title><![CDATA[Linux指令]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/123448813</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/123448813</guid><author>hy3131</author><pubDate>Sat, 12 Mar 2022 19:40:34 +0800</pubDate><description><![CDATA[一.基础指令

1、ls指令

ls：列出当前目录下的所有文件/文件夹的名字

ls/root:列出root下的所有文件/文件夹的名字

ls-l:以详细列表的形式展示

ls-la，ls-a：显示所有文件/文件夹（包含了隐藏文件/文件夹）

ls-lh/root:列出root下的文件/文件夹的名称，以列表的形式并且在显示文档大小的时候以可读性较高的形式显示

2、pwd指令

pwd：即print working directory，打印当前目录

3、cd指令

cd：..:返回到上一级目录

cd/u]]></description><category></category></item><item><title><![CDATA[SQL基础语法]]></title><link>https://blog.youkuaiyun.com/hy3131/article/details/123448411</link><guid>https://blog.youkuaiyun.com/hy3131/article/details/123448411</guid><author>hy3131</author><pubDate>Sat, 12 Mar 2022 19:25:20 +0800</pubDate><description><![CDATA[目录



1.创建库、表，使用库

2.增、删、改、查

3.表关联

4.子查询



1.创建库、表，使用库

CREATE DATABASE IF NOT EXISTS 数据库名 DEFAULT CHARSET utf8;

USE 数据库名；

CREATE TABLE temp

（

id INT PRIMARY KEY AUTO_INCREMENT,
    NAME VARCHAR(50) NOT NULL,
    birthday DATE NOT NU...]]></description><category></category></item></channel></rss>